Safety strap



April 4,y 1939. v H. B. WILSON 2,152,943

SAFETY STRAP Filed Aug. 28, 1937 Patented Apr. 4, 1939 SAFETY STRAP Harry B. Wilson, Wilmette, Ill., assignor to Mathias Klein & Sons, Chicago, Ill., a corporation of Illinois Application August, 28,

. 2 Claims.

My invention relates generally to strapping, and more particularly to safety straps for use by linemen, window Washers, and the like.

In safety straps, the self-evident requirement is that there shall be no danger of breakage or tearing of the strap, since accidental tearing of the strap may readily result in a fatal accident. Linemen, window washers, and the like frequently become habituated to their relativelt7 dangerous occupations, and continue using safety straps which have become partially worn and so do not afford a proper factor of safety. Of course the factor of safety in straps of this character is relatively large so that it is not absolutely essential that a strap be discarded as soon as it becomes slightly worn in one place. However, if, in multi-ply rubberized cord straps, all of the plies of fabric become scuffed and broken, the strap has become worn to an extent such that its further use would be dangerous.

It is therefore an object of my invention to provide improved attention arresting means for indicating when a safety strap has become worn to an extent suii'icient to render its further use hazardous.

A further object is to provide an improved safety strap incorporating an improved arrangement of the plies of cord fabric embodied in the strap.

Other objects will appear from the following description, reference being had to the accompanying drawing, in which:

Fig. 1 is a perspective view of a complete safety strap;

35 Fig. 2 is a somewhat diagrammatic View of the strap showing the various layers thereof separated, more clearly to illustrate its composition;

A Fig. 3 is a transverse sectional view of the strap;

Fig. 4 is an elevation of a portion of a strap which has become worn; and,

Fig. 5 is a transverse sectional View of a threeply strap.

The safety strap of my invention may be utilized in conjunction with fittings of the general type shown in Fig. 1, wherein the strap I 0 is shown as having a safety snap l2 secured at one end thereof, and a similar snap |42 secured in a loop IB of the strap i8, the length of the loop being adjustable by means of a buckle I8 secured to the end of the strap and the tongue of which is engageable in any one of a plurality of holes 20 formed in the strap. The strap, as illustrated in Fig. 1, is adapted for use by linemen and the like, and is normally used by attaching the snaps 1937, Serial No. 161,444

I2 and I4 tothe belt of the wearer after looping the strap about a telephone or telegraph pole. The strap thus supports substantially the whole weight of the user as the latter leans away from the pole while working on the cross arms of the pole and the wires supported thereby. It is therefore essential that the strap have high tensile strength, be readily adjustable in length to accommodate it for different conditions of use, and that it be reasonably light in weight so that it may be easily handled in the usually cramped and awkward positions in which it must be managed. Furthermore, it must be sufciently flexible so that adjustments in its length may easily be made and so that it will readily conform to the shape of the pole or other object by which it is supported without subjecting the cords of the fabric to undue strain.

To attain these and other advantages, the safety strap of my invention is preferably composed of a plurality of plies of cord fabric. As best shown in Fig. 3, the four outer layers or plies 22, 24, 26, and 28 are preferably formed from an integral strip of cord fabric folded back on itself as illustrated. The two central plies SEI and 32 are similarly formed of a single folded strip of cord fabric. The cord fabric plies 22 to 32 are bonded together by thin layers of rubber, and the whole external surface of the strap is completely covered by a layer 34 of rubber. The outer plies 22, 24, 26, and 28 preferably have their cord warp threads running longitudinally of the strap, so as to provide maximum strength in tension lengthwise of the strap, while the inner plies 30, 32 preferably have their warp threads extending perpendicular to those of the other plies so as to provide a greater resistance to deformation of the strap around the holes 20 by the tongue of the buckle I8.

The outer plies 22, 24, 26, 28 are preferably of their natural grayish white color, while the inner plies 30 and 32 are dyed with a dye which does not affect the strength of the fabric and which is preferably of a color which contrasts vividly with the outer plies and with the rubber coating 34. For example, if the rubber coating 34 is black, as is customary, and the outer plies 2U to 28 are white or gray, the two central plies 30 and 32 could be dyed a bright red, bright green, or bright blue, or any other contrasting color.

It will be noted that the outer plies 22, 24, 26,

28 are formed by folding the longitudinal edges of an elongated strip of fabric inwardly so that the edges of an elongated strip of fabric meet substantially at the longitudinal center line of the strip and that thereafter the strip is folded substantially along its longitudinal center line. The inner plies 30 and 32 are formed from a single elongated strip folded along its longitudinal center line, and this` folded strip is inserted between the pairs of plies 22, 24 and 26, 28, formed by the second folding operation of the strip which forms the outer plies. Thus, none of the edges of the fabric are exposed, but instead, the edges are covered by the connecting portion 33, which joins the outer plies 22 and 26. Thus, even though the rubber coating 34 should be worn, it will be necessary for the con` necting portion 33 also to become worn before any edge of the fabric will be exposed to wear by unraveling. This method of folding the strips of fabric thus extends the useful life of the strap.

In the modied form of strap shown in Fig. 5, the two outer plies of cord fabric 36, 38 are preferably formed from a single strip of fabric folded upon itself and over the central ply 40 of the fabric, all plies being covered with a vulcanized coating 42 of relatively soft rubber. In this modication, only the central ply 4|] will be dyed with the contrasting color.

After using the strap for some time, it may become worn, as illustrated in Fig. 4, wherein the strap l has been abraded or otherwise worn sufficiently to expose one of the central plies of fabric 32. Since this ply of fabric is of a vividly contrasting color, its exposure serves as an attention arresting indication that the strap is no longer safe, and that it should be replaced.

In using the safety straps of my invention, the Workman himself, or the foreman having charge of a group of workmen using such straps may very quickly and easily inspect a large number of straps and is provided with a reliable indication of when the wear on the strap has become excessive.

lVfy invention may be embodied in numero-us other forms, all employing the general principle of providing a layer of fabric or other material incorporated within the strap in such position that its exposure, due to wear of the outer plies of the strap, serves as a positive attention arresting indication that it is no longer safe to use the strap. This indicator may be provided by means of a separate thin layer of fabric or other material, or, as disclosed herein, may be provided by making the plies of different and contrasting colors. I therefore desire that the following claims not be limited to the precise construction disclosed, but intend them to include within their scope all such similarly constructed straps wherein substantially the same results are obtained by substantially the same means.

What I claim is:

1. In a safety strap, the combination of an elongated strip of fabric material having its warp threads extending longitudinally thereof, said strip having its longitudinal edges folded inwardly to meet at approximately the longitudinal center line of the strip and being folded along its longitudinal center line so as to bring the edge fold lines adjacent each other, thereby to form four outer plies, and a second fabric strip having its Warp threads extending transversely of the strip and folded along its longitudinal center line, said second strip being enclosed between the pair of plies formed by the folding of said rst strip with its edges adjacent the center fold line of said rst strip, thereby to form two central plies, means to bond said plies together throughout their length, and a weather protecting bonding material completely surrounding all of said plies.

2. In a safety strap of the type which has a buckle and perforations for receiving the tongue of the buckle, the combination of an elongated strip of fabric material having its warp threads extending longitudinally thereof, said strip having its longitudinal edges folded inwardly to meet at approximately the longitudinal center line of the strip and being folded along its longitudinal center line so as to bring the edge fold lines adjacent each other, thereby to form four outer plies, and a second fabric strip having its warp threads extending transversely of the strip and folded along its longitudinal `center line, said second strip being of color readily distinguishable from the color of said first strip and being enclosed between the pair of plies formed bythe folding of said first strip with its edges adjacent the center fold line of said first strip, thereby to form two central plies, means to bond said plies together throughout their length, and a weather protecting bonding material completely surrounding all of said plies.

HARRY B. WILSON. 

